Field of the Invention
The present invention relates to a metal ion recovery device and a metal ion recovery method for selectively recovering a specific metal (for example, lithium) ion in a liquid.
Description of the Related Art
In recent years, the industrial importance of lithium (Li) has been increased, because it is used as a material for lithium ion batteries, and in production of a fuel for nuclear fusion reactors. For example, large-sized lithium ion batteries are used as a power supply for electric vehicles, and for storage of electricity in smart grids and smart houses. For such applications, a technique for inexpensively production of large-sized lithium ion batteries is required. On the other hand, for nuclear fusion reactors, tritium, which serves as a fuel for nuclear fusion, is produced by using Li, and therefore a large amount of lithium is required.
Li can be extracted from ores, however, it is known that Li is contained in the seawater, and an enormous total amount of Li is contained in the whole seawater on the earth. Therefore, if Li can be extracted from the seawater, a large amount of Li can be inexpensively acquired.
Thus, there has been proposed a technique for recovering Li from a solution containing Li. In Patent Documents 1 and 2, there is disclosed a technique for selectively recovering Li by causing Li (ion) to be selectively adsorbed to an adsorber in the seawater, and thereafter desorbing the lithium ion from the adsorber. As the adsorber, the technique disclosed in Patent Document 1 uses manganese oxide, while, with the technique disclosed in Patent Document 2, a vinyl monomer material is used.
By using such a technique, Li can be extracted from the seawater. In addition, by using the same technique, lithium can be selectively recovered from a liquid other than seawater, for example, a waste liquid containing Li (ion). Therefore, such a technique is extremely effective for inexpensively acquiring Li. In addition, by selecting a material for the adsorbing body, a metal other than Li can be recovered by using the same method.